Today marks the 20th anniversary of the publication of Harry Potter and the Philosopher’s Stone. An article on the BBC News website commemorating the milestone remarks that, amongst the numerous and far-reaching impacts the book and film franchise has had upon the world, it has made us (i.e.: the general public) “steamed up about trains”.

We don’t think that’s strictly true, but it is amazing that no railway or main line operator has yet properly tapped into this lucrative market.

The problem with that assertion - that Harry Potter has got the public interested in trains - is that it’s very wide of the mark. The article makes comparison with Thomas the Tank Engine – a franchise that has and still does introduce youngsters to railways, and undoubtedly there are enthusiasts today whose interest stems from the little blue tank engine.

Sure, fans of the books have an interest in the ‘Hogwarts Express’ (that’s the train that ferries Hogwarts’ students from King’s Cross to the wizarding school to muggles like you and I) but it would be very surprising if a significant number have developed an enthusiasm for ‘real’ railways.

Are Harry Potter fans aware that the locomotive – the fictional ­Hogwarts Castle – is in fact ‘Hall’ No. 5972 Olton Hall, and the irony of a ‘Hall’ masquerading as a ‘Castle’? Probably not. But kudos to the filmmakers for giving it a go though, especially as they had very little to go on in the original books. Neither the locomotive nor the train are described in any great detail, so to go to the lengths they did for representing this magical form of transport in the films is to their credit. For instance, the ‘Hogwarts Railways’ crest and lettering on the tender is a marvellous hybrid of British Railways and GWR designs, and lends a sense of historic precedence to proceedings.

Of course, some enthusiasts might bemoan the treatment bestowed upon No. 5972, as well as the fact that it is currently incarcerated inside the Warner Bros. Studio Tour in Leavesden, unlikely to turn a wheel in anger any time soon.

But why has preservation not exploited Harry Potter yet? Yes, there have been half-hearted attempts at trying to capture J. K. Rowling’s audience, but Harry Potter fans both young and old are more discerning than those of, say, Thomas the Tank Engine, and will only be interested in an event that truly encapsulates the spirit of the wizarding world.

Furthermore, a number of preserved railways are starting to shy away from ‘Days Out with Thomas’, as the royalties demanded by HIT Entertainment make such events very expensive to put on, and because they are very weather-dependent, profit for the railways concerned is not strictly guaranteed.

It’s also worth considering who pays to attend ‘Days Out with Thomas’ – parents. Whilst they are designed to appeal to children, at the end of the day it is their mothers and fathers who hold the purse strings, so they have to feel there is something in it for them.

Where Harry Potter has an advantage over the likes of Thomas and Peppa Pig is that it appeals to families. Adults as well as kids love the books and films, and those that grew up with the books as youngsters are now grown up and more than happy to shell out for Potter-related experiences and merchandise.

For instance, the Studio Tour has advertised a Christmas dinner on the set of Hogwarts’ Great Hall (not a locomotive, an actual hall) – for £240 PER PERSON!

And tickets have sold like hot cakes.

Despite the expense, people were still happy to pay 'top dollar' for the experience.

Now, imagine a railway putting on an authentic Harry Potter experience, fully-licensed and of the quality expected by fans of the franchise, and how lucrative it could be for preservation…